Do we really need to floss our teeth?

Almost all dentists recommend flossing, but now we know it has never been scientifically proven to be effective.

By the looks of her teeth, this woman knows her dental hygiene. But does she floss the right way?
(Photo: Lucky Business/Shutterstock)

The vast majority of Americans spend more time feeling guilty about flossing than they do actually flossing their teeth. Dentists beg us to floss — quite literally giving the stuff away in hopes we'll get the hint and use it. The American Dental Association has called flossing "an essential part of taking care of your teeth and gums." Yet a recent investigation by Associated Press reporter Jeff Donn found there's little to no research proving that flossing does the job it's supposed to.

In 1979, the federal government began recommending that people floss their teeth, first in the form of a surgeon general's recommendation and later in the Dietary Guidelines for Americans issued every five years by the U.S. Departments of Health and Human Services and Agriculture. Federal law requires these guidelines to be based on scientific evidence, and it was Donn who noticed the science behind flossing was lacking.

Last year, Donn filled out Freedom of Information Act requests asking the government for the science behind the flossing recommendation. When the 2015-2020 Dietary Guidelines for Americans were released in June of this year, the flossing recommendation had been removed. According to the AP, the feds acknowledged that flossing had never been adequately researched, as required.

So where did the ringing endorsement of flossing come from?

Donn's research — which was backed up by a similar review conducted by an independent panel at the Cochrane Collaboration, an independent network of researchers, professionals, patients, carers and people interested in health — found that of the handful of studies comparing brushing to brushing and flossing, none produced reliable evidence that flossing was beneficial to dental health. The report from the Cochrane group noted the studies "were of poor quality and conclusions must be viewed as unreliable."

Donn also found the majority of flossing studies were funded by companies that manufacture the product, which makes it even more disturbing that none of the studies found conclusive evidence that floss can do what these companies claim it can — namely, reduce plaque and gingivitis.

But Florida dentist Tim Pruett disagrees with the new federal regulations. "Although the official recommendation for flossing might not be the same across the board, flossing helps reduce the risks of interproximal tooth decay and gingivitis," he said, referring to the bad stuff that happens in between your teeth. "These are two of the most common issues dentists see, and the easiest way to prevent these problems ... is with proper flossing."

Pruett did concede that many people simply don't floss correctly, and improper flossing may cause more problems than the good it could do. "Damage can be caused from bad technique, and if you can’t floss correctly, don’t floss at all," he noted.

So do you really need to floss your teeth? National Institutes of Health dentist Tim Iafolla told Donn that while the science is weak, it's still a good idea to floss.

"It's low risk, low cost," Iafolla said. "We know there's a possibility that it works, so we feel comfortable telling people to go ahead and do it."